Is cost a factor, or is cost not a factor? Pick one. You asked if there was clean, consistent renewable, I gave you solar thermal, and acknowledged it's still cost-prohibitive. But I also expect its cost to plummet as experiments turn to production and lessons are learned.

First of all solar thermal is still intermittent and subject to weather and seasonal fluctuations. It has a built in thermal battery so it's consistent on a 24 hour basis, but it's still a variable source of energy.

Cost is a factor but not the only factor. Intermittency is a factor. Geographic limitation is a factor. Land consumption is a factor.

Cheap intermittent energy is an okay supplement, but cannot reliably deliver when it is needed. Hydroelectric and geothermal are great, non-intermittent clean energy but are impossible to build without the right geography. Fossil fuels are cheap, and deliver power anywhere but emit carbon. Nuclear power isn't as cheap as fossil fuels or intermittent sources. But it's the cheapest non-intermittent source that isn't geographically dependent.

If our goal is to fully replace fossil fuels, then nuclear is the best option (besides building geothermal and hydro where we can). Sure, solar thermal can deliver clean energy without the need for additional energy storage. But we could build twice as much capacity with nuclear and use a fraction of the land, and avoid having to build larger plants in the north and south, and avoid seasonal output fluctuations.